1. Field of the Invention
The present invention relates to a spindle head positional error correction method for multi-axis machine tool, and in particular to a spindle head positional error correction method for a multi-axis machine tool including an angular dividing head.
2. Description of the Related Art
A multi-axis machine tool includes an angular dividing head for machining a free curvature. The dividing head has a spindle head mounted thereto, which needs a correction of its positional error at a respective angular position divided by the dividing head. As used herein, xe2x80x9cdividexe2x80x9d means xe2x80x9cindexxe2x80x9d, and xe2x80x9cdeductxe2x80x9d means xe2x80x9cperform indexingxe2x80x9d.
Conventionally, all such positional errors have been individually detected in advance, and stored in a memory, to be read by a controller for correction of an associated error in actual machining.
As the number of dividable angular positions increases, there have been needed a greater time for the detection and a greater capacity for the memory.
The present invention is made with such points in view. It therefore is an object of the present invention to provide a spindle head positional correction method for a multi-axis machine tool including an angular dividing head facilitated in positional correction.
To achieve the object, according to an aspect of the invention, there is provided a spindle head positional error correction method for a multi-axis machine tool including an angular dividing head having a spindle head mounted thereto, the method comprising the steps of determining an error representative vector componentwise representative of a plurality of positional errors with respect to a plurality of axes of the spindle head at a respective angular position dividable by the angular dividing head, and correcting an arbitrary positional error of the spindle head by calculating a component vector of the error representative vector associated with the respective angular position.
According to this aspect of the invention, simply an error representative vector is determined to be based on for correction of an arbitrary positional error. Accordingly, even a short time and a small storage capacity can do for a required positional correction.